1. Field of the Invention
This invention relates to phototherapy goggles and, more particularly, to phototherapy goggles that protect the eyes of an infant.
2. Description of the Related Art
Certain medical treatments can be harmful to the eyes. For example, children born with jaundice have yellow-colored skin due to the presence of high amounts of bilirubin in the blood. Traditional treatment consists of phototherapy in the form of prolonged exposure to high doses of light, and specifically blue light of 425-470 nm wavelength. While light exposure accelerates the removal of excess bilirubin from the infant's body, it can be harmful to the infant's eyes, especially in the high dosages currently employed.
Ultraviolet light, which is usually incidentally emitted, is known to induce keratitis, conjunctivitis, or lens opacities. Wavelengths of visible light, for example, the broad wavelength range of 400-780 nm including the aforementioned blue light range, and near infrared (780-1400 nm), are known to cause photothermal damage at high levels of irradiance. It has also been suggested that exposure of preterm infants' eyes to even ambient light of high intensity may increase the incidence of retinopathy of prematurity by increasing the toxic effects of oxygen.
Therefore, phototherapy goggles, or masks, shaped to generally cover the eyes are used during treatment in an attempt to eliminate or reduce the amount of light the infant's eyes are exposed to. Many conventional masks are designed to seal light out by cinching a flat, fabric-like covering against the eyes. Examples of this approach to infant mask design are disclosed in U.S. Pat. Nos. 4,411,263; 4,502,476; and 4,644,588. As may be appreciated by those of ordinary skill in the art, snug conformance of the mask material to the infant's head will place direct pressure on the eyeball and eyelid, while a loose-fitting mask leaks light about its periphery and may pose the hazard of occluding the infant's nostrils if slippage of the mask occurs. Thus, existing masks may be uncomfortable because they do not allow the eyelid to move normally and, more significantly, they may cause increased ocular pressure. Further, existing flat mask designs often leak from the side and therefore do not adequately protect the infant's eyes from light.
Other masks are known in the art such as the one described in U.S. Pat. No. 5,613,502 (“the '502 patent”). The mask described in this patent once again utilizes a large one-piece protective eye covering formed from three layers of material. The outer layers of the eye covering are formed from a soft napped fabric, and the inner layer is formed from a foam material. The foam is compressed to form large central depressions which provide additional clearance between the eye covering and the infant's eyes. The mask is held in place by a headgear using a stretch gauze, or knit material. Yet, this mask has a number of drawbacks. For instance, this mask is still prone to misalignment. The large one-piece eye covering formed with outer layers made from a soft, napped fabric allows the eye covering to slide around. The eye covering also has a planar geometry which exacerbates this problem. Another drawback inherent in this design is that the planar geometry of this mask does a poor job of distributing forces about the infant's face which can potentially result in discomfort. Yet another drawback to this mask is that it does not conform to the complex geometry of the infant's face well. Leaving gaps between the infant's face and mask results in the potential for light to leak in under the mask.
Another mask, which further advanced the art, is described in U.S. Pat. No. 6,571,799. The mask described in this patent includes a two-part eye covering comprising an outer planar sheath having a pair of oval segments, or annular rings, connected to the rear surface of the planar sheath. The oval segments define cavities to provide clearance between the infant's eyes and the mask. The eye covering is held in place by a headgear, or bonnet, formed from a foam-type material. Unfortunately, this mask also has many of the same drawbacks noted above with respect to the '502 patent. This eye covering is once again formed having outer layers made from fabric. The resulting low coefficient of friction between the infant's face and mask allows the eye covering to slide around. Another drawback inherent in this design is that the geometry of this mask does a poor job of distributing forces about the infant's face which can potentially result in discomfort. Yet another drawback to this mask is that its geometry does not conform to the complex geometry of the infant's face well. Leaving gaps between the infant's face and mask results in the potential for light to leak in under the mask.